Creating An ESP32 Whatsapp CallMeBot

Introduction

In this article, we will learn how to send WhatsApp messages from an ESP32 microcontroller using ESP32 Whatsapp CallMeBot. We will utilize a serial monitor to send messages. Since WhatsApp does not provide direct API access for free, we will use a third-party service like CallMeBot to bridge the ESP32 with WhatsApp.

If you want to explore CallMeBot API service, you can visit: CallMeBot API – Telegram Audio Calls and WhatsApp Messages

Components Required

ESP32 development board
USB cable
Computer with Arduino IDE installed
Active WhatsApp account

Setting Up CallMeBot API

CallMeBot is a free service that allows sending WhatsApp messages via an API. To use CallMeBot:

Save the number +34 621 331 709 in your WhatsApp contacts. (Name it as you wish) — please double-check the number on the CallMeBot website, because it sometimes changes.
Send the following message: I allow callmebot to send me messages
Wait for a reply with your unique API key.

INSTALLING THE ESP32 BOARDS IN Arduino IDE

If your Arduino IDE doesn’t have ESP32 boards installed, here is the guide:

How To Install ESP32 And ESP8266 Boards In Arduino IDE (Step-by-Step Guide) – ArduinoYard

Code to Send WhatsApp Messages

Upload the following code to your ESP32 using the Arduino IDE:

#include <WiFi.h>
#include <HTTPClient.h>

const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";
const char* phoneNumber = "Your_Phone_Number";
const char* apiKey = "Your_API_Key";

void setup() {
    Serial.begin(115200);
    WiFi.begin(ssid, password);
    Serial.print("Connecting to WiFi");
    while (WiFi.status() != WL_CONNECTED) {
        Serial.print(".");
        delay(1000);
    }
    Serial.println("\nConnected to WiFi");
}

void loop() {
    if (Serial.available()) {
        String message = Serial.readStringUntil('\n');
        sendMessage(message);
    }
}

void sendMessage(String message) {
    if (WiFi.status() == WL_CONNECTED) {
        HTTPClient http;
        String url = "https://api.callmebot.com/whatsapp.php?phone=" + String(phoneNumber) + "&text=" + message + "&apikey=" + String(apiKey);
        url.replace(" ", "%20");
        
        http.begin(url);
        int httpCode = http.GET();
        if (httpCode > 0) {
            Serial.println("Message Sent Successfully");
        } else {
            Serial.println("Error Sending Message");
        }
        http.end();
    }
}

How It Works

In Code, add your
- WiFi SSID
- WiFi Password
- Your Whatsapp number where you have created Bot
- The ESP32 Whatsapp CallmeBot API Key.
Select right COM port and ESP32 Board.
Upload the code.
Open Serial Monitor, type the message and press Send.
It will Send the input as a WhatsApp message using CallMeBot API.

ESP32 Serial Monitor

ESP32 WHATSAPP CALLMEBOT

Receiving message from ESP32 to callmebot

Applications and Use Cases

This setup can be used in various IoT applications, including:

Home Automation: Send alerts when motion is detected, doors are opened, or sensors trigger an event.
Industrial Monitoring: Notify users about temperature fluctuations, pressure changes, or machine faults.
Weather Stations: Send periodic weather updates, including temperature and humidity data.
Smart Agriculture: Send notifications for soil moisture levels or automated irrigation systems.
Security Systems: Alert users about unauthorized access, fire alarms, or gas leak detections.
Remote Monitoring: Useful for keeping track of important data in remote locations without direct internet access.

Conclusion

In this tutorial, we successfully sent WhatsApp messages using an ESP32 via a serial monitor. This setup is useful for IoT applications that need remote notifications via WhatsApp. The ability to send alerts and notifications in real-time makes it a valuable addition to smart systems and automation projects.

Here are some Exciting ESP32 projects you might be interested in:

DIY Home Security: Arduino Intruder Alarm System With ESP32 & Blynk Cloud Integration – ArduinoYard

Web Based Weather Station With ESP32 And DHT11 Sensor – ArduinoYard

ESP32 Parking System: Creating A Simple Web Based Parking Space Monitoring System – ArduinoYard

Creating an ESP32 Whatsapp CallMeBot